U.S. patent application number 15/733419 was filed with the patent office on 2021-07-01 for multiplexed immunosignal amplification using hybridization chain reaction-based method.
The applicant listed for this patent is NATIONAL INSTITUTE OF BIOLOGICAL SCIENCES, BEIJING. Invention is credited to Rui LIN, Minmin LUO.
Application Number | 20210198715 15/733419 |
Document ID | / |
Family ID | 1000005508728 |
Filed Date | 2021-07-01 |
United States Patent
Application |
20210198715 |
Kind Code |
A1 |
LIN; Rui ; et al. |
July 1, 2021 |
MULTIPLEXED IMMUNOSIGNAL AMPLIFICATION USING HYBRIDIZATION CHAIN
REACTION-BASED METHOD
Abstract
The invention provides a method for optimizing isHCR for
multiplexed labeling, which combines binder-biomolecule
interactions with hybridization Chain Reaction (HCR).
Inventors: |
LIN; Rui; (Beijing, CN)
; LUO; Minmin; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL INSTITUTE OF BIOLOGICAL SCIENCES, BEIJING |
Beijing |
|
CN |
|
|
Family ID: |
1000005508728 |
Appl. No.: |
15/733419 |
Filed: |
January 26, 2018 |
PCT Filed: |
January 26, 2018 |
PCT NO: |
PCT/CN2018/074364 |
371 Date: |
July 23, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C12Q 1/6804 20130101;
C12Q 1/6832 20130101 |
International
Class: |
C12Q 1/6804 20060101
C12Q001/6804; C12Q 1/6832 20060101 C12Q001/6832 |
Claims
1-33. (canceled)
34. A method for detecting multiple target biomolecules, which
combines binder-biomolecule interactions with Hybridization Chain
Reaction (HCR), wherein orthogonal binders for conjugating
orthogonal initiators and targeting multiple target biomolecules,
and orthogonal initiators directed to orthogonal binders
respectively are used in HCR to allow HCR amplification of multiple
target biomolecules.
35. The method of claim 34, wherein the orthogonal binders are
orthogonal antibodies, orthogonal nanobodies, or orthogonal
antibody fragments of antibodies, wherein the antibodies are
biotinylated antibodies, and the orthogonal HCR initiators are
biotinylated initiators for conjugating the vacant binding sites of
streptavidin, which is capable of conjugating to the biotinylated
antibodies in order to sequentially amplify multiple target
biomolecules.
36. The method of claim 35, wherein the orthogonal HCR initiators
are directly conjugated to the orthogonal antibodies using chemical
linkers, said chemical linker is selected from an amine-reactive
linker containing a succinimidyl ester group, a thiol-reactive
linker or a click chemistry linker.
37. The method of claim 36, wherein the click chemistry linker is
selected from NHS-Azide linker, NHS-DBCO linker, maleimide-azide
linker, and maleimide-DBCO linker.
38. The method of claim 35, wherein the antibody is a secondary
antibody that reacts with a primary antibody specific to an
analyte, the secondary antibody is a IgG or a Nanobody, and the
primary antibody is a IgG, a Nanobody or a scFv.
39. The method of claim 35, wherein the orthogonal binders are
genetically-engineered protein tags for labeling different target
biomolecules, and the orthogonal HCR initiators are conjugated to
tag binding partners respectively, which are capable of binding
tags, preferably, the tag has a chemical group nonreactive toward a
biomolecule, and said chemical group is selected from an amine
moiety, a carboxyl moiety, a thiol moiety and a glycosylated
modification moiety, preferably, the tag is CLIP-tag or
Halo-tag.
40. The method of claim 39, wherein the HCR initiators are
conjugated to tag binding partners selected from SpyCatcher,
SnoopCatcher, benzylguanine (BG), and scFv, and subsequently are
used to detect the subcellular localization of the
genetically-encoded tags selected from SpyTag, SnoopTag, SNAP-tag,
and GCN4-tag respectively.
41. The method of claim 34, wherein an amplifier or a pair of
amplifiers are terminally modified or internally modified with a
chemical group and/or a fluorescent dye, which allows initiating
further rounds of amplification, said chemical group is selected
from biotin, digoxigenin, acrydite, amine, succinimidyl ester,
thiol, azide, TCO, Tetrazine, Alkyne, and/or DBCO, and said
fluorescent dye is selected from FITC, Cyanine dyes, Dylight
fluors, Atto dyes, Janelia Fluor dyes, Alexa Fluro 546, Alexa Fluor
488, and Alexa Fluor 647, preferably, a pair of fluorophore-tagged
amplifiers are added to the final round of the multiple-round HCR
for visualization.
42. The method of claim 41, wherein the amplifiers are modified at
internal positions, which are accessible to streptavidin and which
serve as anchors for each successive round of branching in
multi-round isHCR.
43. The method of claim 34, further comprising using grapheme oxide
(GO) for absorbing unassembled HCR amplifiers; or further
comprising using grapheme oxide (GO) for absorbing unassembled HCR
amplifiers and quenching the fluorescence, wherein the amplifiers
are terminally modified and/or internally modified with fluorescent
dye.
44. The method of claim 43, wherein GO has a particle size of
<500 nm.
45. A kit for detecting multiple target biomolecules, which
comprises (1) orthogonal binders; (2) orthogonal HCR initiators;
and (3) orthogonal pairs of HCR amplifiers, wherein each of HCR
initiators has a region for hybridizing with a HCR amplifier, and a
region for conjugating a binder, and the orthogonal binders target
multiple target biomolecules respectively to allow HCR
amplification directed to multiple target biomolecules.
46. The kit of claim 45, wherein the orthogonal binders are
orthogonal antibodies, orthogonal nanobodies, or orthogonal
antibody fragments of antibodies, preferably, the orthogonal
antibodies are orthogonal biotinylated antibodies, and the
orthogonal HCR initiators are biotinylated initiators for
conjugating the vacant binding sites of streptavidin, which is
capable of conjugating to the biotinylated antibodies in order to
sequentially amplify multiple target biomolecules.
47. The kit of claim 46, wherein the orthogonal HCR initiators are
directly conjugated to the orthogonal antibodies using chemical
linkers, said chemical linker is selected from an amine-reactive
linker containing a succinimidyl ester group, a thiol-reactive
linker or a click chemistry linker, preferably, the click chemistry
linker is selected from NHS-Azide linker, NHS-DBCO linker,
maleimide-azide linker, and maleimide-DBCO linker.
48. The kit of claim 46, wherein the antibody is a secondary
antibody that reacts with a primary antibody specific to an
analyte, the secondary antibody is a IgG or a Nanobody, and the
primary antibody is a IgG, a Nanobody or a scFv.
49. The kit of claim 45, wherein the orthogonal binders are
genetically-engineered protein tags for labeling different target
biomolecules, and the orthogonal HCR initiators are conjugated to
tag binding partners, which are capable of binding tags,
preferably, the tag has a chemical group nonreactive toward a
biomolecule, said chemical group is selected from an amine moiety,
a carboxyl moiety, a thiol moiety and a glycosylated modification
moiety, preferably, the tag is CLIP-tag or Halo-tag.
50. The kit of claim 45, wherein the HCR initiators are conjugated
to tag binding partners selected from SpyCatcher, SnoopCatcher,
benzylguanine (BG), and scFv, and subsequently are used to detect
the subcellular localization of the genetically-encoded tags
selected from SpyTag, SnoopTag, SNAP-tag, and GCN4-tag
respectively.
51. The kit of claim 45, wherein an amplifier or a pair of
amplifiers are terminally modified or internally modified with a
chemical group and/or a fluorescent dye, which allows initiating
further rounds of amplification, said chemical group is selected
from biotin, digoxigenin, acrydite, amine, succinimidyl ester,
thiol, azide, TCO, Tetrazinc, Alkyne, and/or DBCO, and said
fluorescent dye is selected from FITC, Cyanine dyes, Dylight
fluors, Atto dyes, Janelia Fluor dyes, Alexa Fluro 546, Alexa Fluor
488, and Alexa Fluor 647, preferably, a pair of fluorophore-tagged
amplifiers is added to the final round of the multiple-round HCR
for visualization.
52. The kit of claim 51, wherein the amplifiers are modified at
internal positions, which are accessible to streptavidins and which
serve as anchors for each successive round of branching in
multi-round isHCR.
53. The kit of claim 45, further comprising grapheme oxide (GO) for
absorbing unassembled HCR amplifiers; or further comprising
grapheme oxide (GO) for absorbing unassembled HCR amplifiers and
quenching the fluorescence, wherein the amplifiers are terminally
modified and/or internally modified with fluorescent dye,
preferably, GO has a particle size of <500 nm.
Description
BACKGROUND
[0001] Owing to their ease of use, speed, and cost effectiveness,
antibody-based immunoassays remain the most popular methods for
detecting and identifying the location of proteins and other
biomolecules in biological samples. These methods use a primary
antibody that binds selectively to a target molecule (antigen), and
this antibody-antigen interaction can be visualized via a
conjugated reporter or a labeled secondary antibody that can
recognize and react with the primary antibody-epitope complex (Han,
K. N., Li, C. A. & Seong, G. H. Annu. Rev. Anal. Chem. 6,
119-141 (2013)). A major limitation in the use of immunoassays is
that the low abundance of a given target molecule in a sample often
necessitates signal amplification before detection is possible.
Amplification can be achieved using conjugated enzymes such as
horseradish peroxidase (HRP) and alkaline phosphatase, which
catalyze the deposition of chromogenic substrates on target
complexes (Bobrow, M. N., Harris, T. D., Shaughnessy, K. J. &
Litt, G. J. J. Immunol. Methods 125, 279-285 (1989)). Fluorogenic
substrates, especially those based on HRP-tyramide reaction
chemistries, have been developed to support high-resolution
fluorescence microscopy (Stack, E. C., Wang, C., Roman, K. A. &
Hoyt, C. C. Methods 70, 46-58 (2014)). Although very useful and
widely-employed, current amplification methods have several
drawbacks: they often generate high background, they can reduce
spatial resolution due to dye diffusion, they are difficult to use
for the simultaneous detection of multiple amplified signals
(Carvajal-Hausdorf, D. E., Schalper, K. A., Neumeister, V. M. &
Rimm, D. L. Lab. Invest. 95, 385-396 (2015)), and they are
unsuitable for use with large-volume samples in several powerful
new tissue expansion and clearing techniques.
[0002] In this invention, we find that an enzyme-free amplification
approach could overcome many of these limitations. In particular,
hybridization chain reaction (HCR) technology is adapted to amplify
immunosignals. HCR, which is based on recognition and hybridization
events that occur between sets of DNA hairpin oligomers that
self-assemble into polymers, has to date been used primarily for
the amplification of mRNA signals from in situ hybridization
samples (Choi, H. M. T., Beck, V. A. & Pierce, N. A. ACS Nano
8, 4284-4294 (2014); Shah, S. et al. Development 143, 2862-2867
(2016)) and more recently for the detection of protein-protein
interactions (Koos, B. et al. Nat. Commun. 6, 7294 (2015)), and
more recently for the detection of protein-protein interactions
(Koos, B. et al. Nat. Commun. 6, 7294 (2015)). In a typical usage
case, nucleic acid probes complementary to the target mRNA molecule
are used as `initiator` oligos. Starting from the initiator oligos,
a series of polymerization reactions are used to add
fluorophore-labeled nucleic acid `amplifier` oligos to the target
mRNA-initiator complex; the fluorophores are then visualized.
SUMMARY OF THE INVENTION
[0003] The invention provides a method for optimizing isHCR for
multiplexed labeling, which combines binder-biomolecule
interactions with hybridization Chain Reaction (HCR), wherein the
initiators used in the isHCR are modified directed to multiple
targets respectively to allow simultaneous isHCR amplification of
multiple targets. The invention also provides a kit for performing
the method for optimizing isHCR for multiplexed labeling.
[0004] In the first aspect, the invention provides a method for
detecting multiple target biomolecules, which combines
binder-biomolecule interactions with hybridization Chain Reaction
(HCR), wherein orthogonal binders for conjugating orthogonal
initiators and targeting multiple target biomolecules, and
orthogonal initiators directed to orthogonal binders respectively
are used in HCR to allow HCR amplification of multiple target
biomolecules.
[0005] In the second aspect, the invention provides a kit for
detecting multiple target biomolecules, which comprises (1)
orthogonal binders; (2) orthogonal HCR initiators; and (3)
orthogonal pairs of HCR amplifiers' wherein each of HCR initiators
has a region for hybridizing with a HCR amplifier, and a region for
conjugating a binder, and the orthogonal binders target multiple
target biomolecules respectively to allow HCR amplification
directed to multiple target biomolecules.
[0006] The binder can be an antibody, a fragment of an antibody, or
a genetically-engineered protein tag. If the orthogonal binders are
orthogonal antibodies, the antibodies may be biotinylated
antibodies, and the orthogonal HCR initiators may be biotinylated
initiators for conjugating the vacant binding sites of
streptavidin, which is capable of conjugating to the biotinylated
antibodies in order to sequentially amplify multiple target
biomolecules.
[0007] Preferably, the orthogonal HCR initiators may be directly
conjugated to the orthogonal binders using chemical linkers so as
to simplify the multiplexed labeling procedure. The chemical
linkers can be amine-reactive linkers, thiol-reactive linkers or
click chemistry linkers. The amine-reactive linkers can be linkers
containing succinimidyl ester group. The click chemistry linkers
can be linkers containing click chemistry functional groups, such
as NHS Azide linkes, NHS-DBCO linkers, maleimide-azide linkers, or
maleimide-DBCO linkers. For example, the orthogonal HCR initiators
can be conjugated directly onto the binders via SMCC or NHS-Azide
linkers. This direct conjugation allows simultaneous HCR
amplification directed to multiple target biomolecules.
[0008] Preferably, the antibody may be a secondary antibody that
reacts with a primary antibody specific to an analyte, the
secondary antibody is a IgG or a Nanobody, and the primary antibody
is a IgG, a Nanobody or a scFv.
In the situation that the binder is a genetically-engineered
protein tag, the orthogonal HCR initiators can be conjugated to tag
binding partners, which are capable of binding tags labeling
different target biomolecules. The biomolecules can be
biomolecules, such as proteins, small signaling molecules,
neurotransmitters, etc., in the cells. The tag has a chemical group
nonreactive toward a biomolecule, said chemical group is selected
from an amine moiety, a carboxyl moiety, a thiol moiety and a
glycosylated modification moiety. The HCR initiators are conjugated
to tag binding partners, and subsequently are used for HCR
amplification to detect tags. The persons skilled in the art may
easily choose the tags and tag binding partners as desired.
[0009] The tags may be orthogonal tags targeting different cellular
locations and being expressed in cultured cells. In this situation,
the HCR initiators may be conjugated to tag binding partners (for
example, SpyCatcher, SnoopCatcher, benzylguanine (BG), and scFv),
and subsequently are used to detect the subcellular localization of
the genetically-encoded tags (SpyTag, SnoopTag, SNAP-tag, and
GCN4-tag). CLIP-tag and Halo-tag, two chemical tags that are
orthogonal to the SNAP-tag technology, could also be adopted for
HCR in a fashion similar to SNAP-tag. Recently, novel mini-protein
binders that target small ligands were developed using de novo
protein design. These new ligand-binder pairs, such as
digoxigenin/DIG10.3 also can be used with HCR.
[0010] Therefore, these extensions of HCR concept beyond
biotin-streptavidin interactions and beyond primary and secondary
antibodies demonstrate that HCR can be implemented in a highly
multiplexed fashion. These direct conjugation strategies will also
reduce the size of isHCR amplification complexes.
[0011] The isHCR may be multi-round isHCR, in which an amplifier or
a pair of amplifiers are modified to access branched multiple-round
amplification in order to branch and grow the HCR polymers.
[0012] The HCR initiators can be hybridized with any of several
types of self-assembling DNA HCR amplifiers, including a
fluorophore-labeled amplifier oligo that can be used for
visualization of the original target signal.
[0013] The HCR amplifiers (H1 and H2) used in the present
multi-round isHCR can be terminally modified or internally modified
with chemical groups and/or fluorescent dyes, which allows
initiating further rounds of amplification. In this situation, the
amplifiers (H1 and H2) can be terminally modified or internally
modified with biotin, digoxigenin, acrydite, amine, succinimidyl
ester, thiol, azide, TCO, Tetrazine, Alkyne, and/or DBCO.
Fluorescent dye, such as FITC, Cyanine dyes, Alexa Fluors, Dylight
fluors, Atto dyes or Janelia Fluor dyes, can be also tagged to the
amplifiers together with biotin, digoxigenin, acrydite, amine,
succinimidyl ester, thiol, azide, TCO, Tetrazine, Alkyne, and/or
DBCO. For example, amplifiers can be labeled with bitoin groups.
Once these DNA-biotin amplifiers have self-assembled and joined the
growing isHCR polymer, their biotins can be reacted with
newly-added streptavidins (and hence can be reacted with more HCR
initiators, etc.), thereby initiating further rounds of polymer
elaboration. A pair of signal molecule-modified amplifiers (e.g., a
pair of fluorophore-tagged amplifiers) can be added to the final
round of isHCR.sup.n for visualization.
[0014] Preferably, the amplifiers are modified at internal
positions, which are more accessible to the binding partners, such
as streptavidins, which serve as anchors for each successive round
of branching in multi-round isHCR (isHCR.sup.n).
[0015] The present method may also comprise using grapheme oxide
(GO) to absorb unassembled HCR amplifiers. If the amplifiers are
terminally modified and/or internally modified with fluorescent
dye, grapheme oxide (GO) may also quench the fluorescence.
Therefore, the kit of the present invention may also comprise
grapheme oxide. Graphene Oxide in the present invention has a
particle size of <500 nm. Crucially, in addition to abolishing
the fluorescence of HCR amplifiers, the addition of HCR initiators
along with HCR amplifiers and GO resulted in substantial recovery
of fluorescence, likely because the initiators triggered the
formation of double-strand-nicked polymers of HCR amplifiers,
thereby protecting them from the adsorption activity of GO. That
is, GO can be used to suppress background levels, further enhancing
the performance of isHCR.
[0016] The addition of GO reduced the background but did not
diminish the signal intensity, resulting in an improved
signal-to-noise ratio as compared to isHCR amplification without
GO. Surprisingly, further analysis using antibody serial dilution
experiments showed that isHCR with GO significantly increased
signal intensity as compared to a standard IHC staining method,
achieving a greater than 80.times. amplification factor when the
primary antibody was highly diluted.
[0017] The invention encompasses all combination of the particular
embodiments recited herein.
BRIEF DESCRIPTION OF THE FIGURES
[0018] FIG. 1. Multiplexed labeling using isHCR.
[0019] FIG. 2. Simultaneous detection of multiple targets using
isHCR.
DESCRIPTION OF PARTICULAR EMBODIMENTS OF THE INVENTION
[0020] In the first embodiment, we established the use of two
biotinylated secondary antibodies in combination with two
orthogonal DNA HCR initiators, which allows isHCR to sequentially
amplify two targets in the same brain section sample (FIG. 1a).
[0021] In the second embodiment, we directly conjugated DNA HCR
initiators to secondary antibodies via SMCC or NHS-Azide linkers
(FIG. 2a). This modification allows simultaneous isHCR
amplification of multiple targets. We successfully performed
multiplexed isHCR amplification using initiator-labeled secondary
antibodies in western blotting (FIG. 2b), immunostaining of
cultured cells (FIG. 2c), and immunostaining of brain sections
(FIG. 2d).
[0022] In the third embodiment, with the goal of expanding the
modularity of the isHCR platform yet further, we tested whether a
variety of genetically-engineered protein tags could be added to
target proteins in cells to enable the direct binding of targets to
HCR initiators. Three orthogonal tags targeting different cellular
locations (SpyTag for cell nuclei, SNAP-tag for mitochondria, and
smFP_GCN4 for cell membranes) were expressed in cultured cells. DNA
HCR initiators were conjugated to tag binding partners (SpyCatcher,
benzylguanine (BG), and scFv), and these were subsequently used for
isHCR amplification to detect the subcellular localization of the
genetically-encoded tags (FIG. 2e). Strong and correctly localized
signals were observed for each tag.
[0023] In the fourth embodiment, we next expressed membrane-bound
GFP in brains and confirmed that HCR initiators conjugated to GFP
nanobodies22 could bind directly to GFP, allowing for subsequent
polymerization and detection of HCR amplifiers in brain sections
(FIG. 1b).
[0024] In the fifth embodiment, we expressed the SNAP-tag in mouse
brains and applied BG-functionalized HCR initiators for direct
detection and amplification (FIG. 1c, d). We noted that labeling
neurons with a monomeric SNAP-tag only generated weak signals at
soma (FIG. 1d middle panel). We therefore employed a tandem
SNAP-tag to enhance the labeling intensity. This optimization
greatly increased the signal intensity and allowed for the
detection of distal axons of labeled neurons (FIG. 1d bottom
panel).
[0025] HCR is the abbreviation of Hybridization Chain Reaction.
When a single-stranded DNA initiator is added to a reaction system,
it opens a hairpin of one species (H1 amplifier), exposing a new
single-stranded region that opens a hairpin of the other species
(H2 amplifier). This process, in turn, exposes a single-stranded
region identical to the original initiator. The resulting chain
reaction leads to the formation of a nicked double helix that grows
until the hairpin supply is exhausted.
[0026] isHCR in the present invention combines binder-biomolecule
interaction with hybridization Chain Reaction (HCR), wherein the
binder may be an antibody or a genetically-engineered protein tag
for labeling a target biomolecule.
[0027] Click chemistry is a class of biocompatible reactions
intended primarily to join substrates of choice with specific
biomolecules. Click chemistry is not a single specific reaction,
but describes a way of generating products that follow examples in
nature, which also generates substances by joining small modular
units. In general, click reactions usually join a biomolecule and a
reporter molecule. Click chemistry is not limited to biological
conditions: the concept of a "click" reaction has been used in
pharmacological and various biomimetic applications. However, they
have been made notably useful in the detection, localization and
qualification of biomolecules.
[0028] Antibody in the present invention includes but not limited
to traditional IgGs and nanobodies.
EXAMPLES
[0029] Methods and Materials
[0030] Reagents and reagent preparation. DNA oligos were
synthesized by Thermo Fisher Scientific and Sangon Biotech.
Detailed sequences and modifications of DNA oligos can be found in
Table 1. All oligos were dissolved in ddH.sub.2O and stored at
-20.degree. C. Benzylguanine (BG)-labeled oligos were prepared by
first mixing NH.sub.2-Oligo (2 mM, 4 .mu.L), HEPES (200 mM, 8
.mu.L; pH=8.5), and BG-Gal-NHS (20 mM in DMSO, 12 .mu.L; S9151S,
NEB) for 30 min at room temperature, and then purified using Micro
Bio-Spin P-6 Gel columns (7326221, Bio-Rad).
[0031] The detailed information for antibodies and fluorescent
reagents is shown in Table 2. Dextran sulfate (D8906) were
purchased from Sigma-Aldrich. Graphene Oxide (GO, XF020, particle
size <500 nm, C/O ratio=1.6) was obtained from Nanjing
XFNANO.
[0032] Plasmid construction and AAV packaging. The genes encoding
SNAPf, SpyCatcher, and GFP nanobody (LaG-16-2) were synthesized
according to original reports. 4.times.SNAPf sequence was assembled
by fusing four SNAPf-encoding sequences with short peptide linkers
using Gibson cloning. scFv-GCN4-HA-GB1 sequence was amplified from
pHR-scFv-GCN4-sfGFP-GB1-NLS-dWPRE (Addgene plasmid #60906, a gift
from Ron Vale). The amino acid sequence smFP_GCN4 was designed
based on the originally-reported smFPs sequence (Table 3). For
membrane targeting, a GAP43-palmitoylation sequence was added by
PCR to the 5' end of GFP, SNAPf, and smFP_GCN4 (hereafter named
mGFP, mSNAPf and msmFP_GCN4). Two tandem mitochondria targeting
sequences from human Cox8a were amplified by PCR from genomic DNA
of HeLa cells, and added to the 5' end of SNAPf by Gibson assembly
(hereafter named mitoSNAP). H2B and human GBP1 sequence was
amplified by PCR from genomic DNA of HeLa cells. A single SpyTag
sequence was added to the 3' end of H2B by PCR (hereafter named
H2B-SpyTag). mGFP, mitoSNAP, H2B-SpyTag, and msmFP_GCN4 were cloned
into the pcDNA3.1 vector. scFv-GCN4-HA-GB1 and SpyCatcher were
cloned into the pET-21a vector for bacterial cytosolic expression.
LaG-16-2 was cloned into the pET-22b vector for bacterial
periplasmic expression. AAV-DIO-mGFP was constructed as previously
described. AAV-DIO-mSNAPf and AAV-DIO-4.times.SNAPf were
constructed by inserting the sequences encoding mSNAPf or
4.times.SNAPf, in an inverted orientation, into an AAV-EF1a-DIO
backbone derived from AAV-EF1a-DIO-hChR2(H134R)-mCherry (a gift
from Karl Deisseroth). AAV vectors were packaged into the AAV2/9
serotype, with titers of 1-5.times.10.sup.12 viral particles
.quadrature.mL.sup.-1.
[0033] Purification of recombinant protein. E. coli BL21 (DE3)
cells harboring pET-21a-scFv-GCN4-HA-GB1 or pET-21a-SpyCatcher were
grown in lysogeny broth (LB) medium supplemented with 100 .mu.g
.quadrature.mL.sup.-1 ampicillin. Protein expression was induced
with IPTG at a concentration of 0.1 M for 3 h at 37.degree. C.
[0034] Cells were then pelleted by a 20-min spin at 2,000.times.g
at 4.degree. C. Cells were lysed via ultrasonic sonication.
Cellular debris was removed via 1 h of centrifugation at
39,000.times.g at 4.degree. C. The supernatant was bound to
His-Select nickel affinity resin, washed with His-wash buffer (20
mM NaH.sub.2PO.sub.4, pH 8.0, 1 M NaCl, 20 mM imidazole), eluted
with His-elution buffer (20 mM sodium phosphate, pH 8.0, 0.5 M
NaCl, 250 mM imidazole), and the eluate was then dialyzed with
phosphate buffer saline (PBS).
[0035] LaG-16-2 was expressed and purified according to the
original report. In brief, E. coli BL21 (DE3) cells harboring
pET-22b-LaG-16-2 were grown in LB medium supplemented with 100
.mu.g.quadrature.mL.sup.-1 ampicillin. Protein expression was
induced with IPTG at a concentration of 0.1 M for 20h at 12.degree.
C. Cells were pelleted via a 10-min of centrifugation at
5,000.times.g at 4.degree. C. The periplasmic fraction was isolated
by osmotic shock. This fraction was then bound to His-Select nickel
affinity resin and purified as described above.
[0036] Protein-HCR DNA Initiator conjugation. The conjugation was
performed using Maleimide-PEG2-NHS (SMCC, 746223, Sigma-Aldrich) or
NHS-Azide (synthesized or purchased from Thermo Fisher Scientific,
26130) as linkers. For Maleimide-PEG2-NHS conjugation, proteins
(IgGs, scFv, LaG-16-2 and SpyCatcher) were dialyzed into phosphate
buffered saline (PBS, pH 7.4) and reacted with Maleimide-PEG2-NHS
(7.5-fold molar excess) at room temperature for 2 h. Excess
crosslinkers were removed from maleimide-activated proteins using
Zeba spin columns (7000 MWCO). In parallel, thiol-modified HCR
initiators were reduced using dithiothreitol (DTT, 100 mM) in PBS
(1 mM EDTA, pH 8.0) for 2 h at room temperature, and then purified
using Micro Bio-Spin P-6 Gel columns. The maleimide-activated
proteins and reduced initiators (15-fold molar excess for IgGs;
7.5-fold for scFv, LaG-16-2; 3-fold for SpyCatcher) were mixed and
reacted at room temperature for 2 h. HCR initiator-labeled proteins
were purified using Amicon Ultra Centrifugal Filters (50 kDa MWCO)
or Zeba spin columns (7000 MWCO).
[0037] For NHS-Azide conjugation, proteins were dialyzed into
phosphate buffered saline (PBS, pH 7.4) and reacted with NHS-Azide
(7.5-fold molar excess) at room temperature for 2 h. Excess
crosslinkers were removed from azide-activated proteins using Zeba
spin columns (7000 MWCO). The azide-activated proteins were mixed
with DBCO-labeled HCR initiators (15-fold molar excess for IgGs;
7.5-fold for scFv, LaG-16-2; 3-fold for SpyCatcher) and then
reacted at room temperature for 12h. HCR initiator-labeled proteins
were purified using Amicon Ultra Centrifugal Filters (50 kDa MWCO)
or Zeba spin columns (7000 MWCO).
[0038] Cell culture and bacterial infections. HEK293T cells (ATCC
CRL-3216) and HeLa cells (ATCC CCL-2) were used for the
cultured-cell staining experiments. Cells were seeded on 12 mm #1.5
coverglass slips. Transfection was done using PEI. Cells were fixed
with paraformaldehyde before subsequent experiments. The S.
typhimurium infection was performed according to a previous
report.
[0039] Mice and virus injection. Animal care and use were in
accordance with the institutional guidelines of the National
Institute of Biological Sciences, Beijing (NIBS), as well as the
governmental regulations of China.
[0040] Adult (8-12 weeks old) SERT-Cre mice [strain name:
B6.Cg-Tg(Slc6a4-Cre)ET33Gsat; MMRRC; Davis, Calif., USA],
CaMKIIa-Cre [strain name: B6.Cg-Tg(Camk2a-cre)T29-1Stl/J], ChAT-Cre
[strain name: B6; 129S6-Chattm2(cre)Lowl/J], and C57BL/6N mice of
either sex were used. Mice were maintained with a 12/12 photoperiod
(light on at 8 AM) and were provided food and water ad libitum.
Mice were anaesthetized with pentobarbital (i.p., 80
mg.times.kg.sup.-1) before surgery, and then placed in a mouse
stereotaxic instrument. For each mouse, 350 nL of virus
(AAV-DIO-mGFP, AAV-DIO-mSNAPf, or AAV-DIO-4.times.SNAPf) was
infused into the target areas of mice via a glass pipette at rate
of 50 nLmin.sup.-1. All subsequent experiments were performed at
least 3 weeks after virus injection to allow sufficient time for
transgene expression.
[0041] Tissue sample preparation. Mice were anesthetized with an
overdose of pentobarbital and perfused intracardially with PBS,
followed by paraformaldehyde (PFA, 4% wt/vol in PBS). Tissues were
dissected out and postfixed in 4% PFA for 4 h at room temperature
or 1 d at 4.degree. C. Tissue samples were first dehydrated in 30%
sucrose solution for preparing thin sections (50 .mu.m). Thin
sections were prepared on a Cryostat microtome (Leica CM1950).
[0042] Immunohistochemistry. The detailed information, working
concentrations, and incubation times for antibodies can be found in
Table 2. For brain sections and cultured cells, samples were
permeabilized with 0.3% Triton X-100 in PBS (PBST) and blocked in
2% BSA in PBST at room temperature for 1 h. Sections were then
incubated with primary antibodies. Samples were washed three times
in PBST and were then incubated with biotinylated or HCR
initiator-conjugated secondary antibodies. For control experiments,
we used a mixture containing equal amounts of
fluorophore-conjugated secondary antibodies and biotinylated
secondary antibodies. Samples were then washed again three times in
PBST. The biotinylated secondary antibodies were visualized by
fluorophore-conjugated Streptavidin or DNA-fluorophore HCR
amplifiers. HCR initiator-conjugated secondary antibodies were
visualized by DNA-fluorophore HCR amplifiers.
[0043] Labeling of isHCR initiators. All reagents were dissolved in
HCR amplification buffer [5.times. sodium chloride citrate (SCC
buffer), 0.1% vol/vol Tween-20, and 10% wt/vol dextran sulfate in
ddH.sub.2O]. After labeling with biotinylated secondary antibodies,
samples were incubated in 1 .mu.gmL.sup.-1 streptavidin at room
temperature for 30 min. After being washed three times in PBST,
samples were incubated with 0.5 .mu.M DNA-biotin HCR initiators at
room temperature for 30 min. Samples were then washed three times
and stored in PBST.
[0044] For multiplexed amplification using multiple biotinylated
secondary antibodies (FIG. 1a), the immunosignals of target
proteins were amplified using isHCR sequentially. That is, after
being labeled with two primary antibodies, samples were incubated
with one of two biotinylated secondary antibodies against a primary
antibody; the basic isHCR amplification protocol was then used to
amplify the signal of the secondary antibody. Next, before the
application of the second of the two biotinylated secondary
antibodies, brain sections were incubated with streptavidin (0.5
.mu.gmL.sup.-1, 30 min at room temperature) to block any unbound
biotin units remaining on the first secondary antibody; biotin (5
ngmL.sup.-1, 30 min at room temperature) was then added to saturate
the biotin binding sites of the streptavidin. Having blocked the
reactivity of the first biotinylated secondary antibody, the second
biotinylated secondary antibody was added and then amplified. For
multiplexed labeling using HCR initiator-conjugated secondary
antibodies (FIGS. 2c, 2d), the snap-cooled DNA-fluorophore HCR
amplifiers are applied directly to initiator-labeled samples and
then amplified with the basic isHCR amplification protocol (i.e.,
lacking any streptavidin step).
[0045] The labeling of genetically encoded tags (SNAP-tag, SpyTag,
GFP, and smFP_GCN4) with HCR initiators was conducted as follows
(FIG. 2e and FIG. 1b-1d). After membrane permeabilization,
cultured-cell or brain-section samples were incubated with
appropriate binding partners. For SNAP-tag labeling, we applied 0.1
.mu.M BG-labeled HCR initiators or 0.5-1 .mu.M SNAP-Surface Alexa
Fluor 546 and incubated these samples at room temperature for 1h.
For SpyTag labeling, we applied 25 .mu.M HCR initiator-labeled
SpyCatcher and incubated these samples at room temperature for 2h.
For mGFP-labeled samples, we applied 1 .mu.gmL.sup.-1HCR
initiator-labeled LaG-16-2 and incubated these samples overnight at
4.degree. C. For smFP_GCN4 labeling, we applied 5 .mu.gmL.sup.-1
HCR initiator-labeled scFv-GCN4-HA-GB1 and incubated these samples
at room temperature for 1h. PBS was used as incubation buffer for
SNAP-Surface Alexa Fluor 546. HCR amplification buffer was used for
all HCR initiator-containing reagents. Samples were then washed
three times with PBST, and stored in PBST.
[0046] isHCR amplification. Note that while the experimental steps
regarding the isHCR initiators varied according the conjugation
strategies, the basic isHCR amplification process is common to all
of the experiments. First, HCR amplification buffer was prepared
[5.times. sodium chloride citrate (SCC buffer), 0.1% vol/vol
Tween-20, and 10% wt/vol dextran sulfate in ddH.sub.2O]. Next, a
pair of DNA-fluorophore HCR amplifiers were snap-cooled separately
in 5.times.SSC buffer by heating at 95.degree. C. for 90s and
cooling to room temperature over 30 min. Both of these amplifiers
were then added to amplification buffer (typically to a final
concentration of 12.5 nM for thin sections, or 150 nM for large
volume samples). isHCR amplification proceeded as samples were
incubated with this buffer overnight at room temperature, and free
amplifiers were then removed by washing the three times with PBST
prior to signal detection. Note that an additional graphene oxide
step was added to this basic process for applications that demands
background suppression. Briefly, to include the quenching step, GO
(20 .mu.gmL.sup.-1) was mixed with the amplifiers in amplification
buffer. The amplifier/GO mixture was vortexed thoroughly and
incubated at room temperature for at least 5 min before being added
to initiator-labeled samples.
[0047] To perform multi-round amplification, we used DNA-biotin HCR
amplifiers. Before use, DNA-biotin HCR amplifiers were snap-cooled.
Samples were incubated with 12.5 nM DNA-biotin HCR amplifiers
overnight at room temperature. After extensive washing,
streptavidin (1 .mu.gmL.sup.-1) was applied again to start the next
round of amplification. The procedure of adding DNA-biotin HCR
amplifiers and then streptavidin was repeated two or three times to
achieve desired signal intensity. DNA-fluorophore amplifiers (12.5
nM) were used in the final round to visualize the signals. For
control experiments, biotin and Alexa Fluor-488 dual-labeled HCR
amplifiers were used for the first round of amplification. Alexa
Fluor-546-labeled HCR amplifiers were used for the second round of
amplification.
[0048] Fluorescence microscopy. Confocal microscopy was performed
on a Zeiss Meta LSM510 confocal scanning microscope using a
10.times.0.3 NA, a 20.times.0.5 NA, a 63.times.1.4 NA, or a
100.times.1.3 NA objective, or on a Zeiss LSM880 confocal scanning
microscope using a 20.times.0.5 NA or a 40.times.0.75 NA objective.
Images were processed and measured with FIJI and Matlab.
[0049] To image the entire brain sections, we performed wide-field
fluoresce imaging using the Olympus VS120 virtual microscopy slide
scanning system with a 10.times. objective. For slide scanner
imaging, brain sections from both groups on the same slide were
imaged during the same imaging run using identical light intensity
and exposure time. The images were acquired at 16 bit and were
converted directly to the TIFF format for publication.
[0050] Statistical significance was determined using t-test or
Kolmogorov-Smirnov test. P<0.05 was considered significant.
TABLE-US-00001 TABLE 1 Oligo nucleotide sequences and modifications
Name Sequence (5' to 3') Modifications B1 I2
ATATAgCATTCTTTCTTgAggAgggCAgCAAACgggAAgAg 5' Biotin (SEQ ID NO: 1)
B1 I2 Amine ATATAgCATTCTTTCTTgAggAgggCAgCAAACgggAAgAg 5' Amine (SEQ
ID NO: 1) B1 I2 Thiol ATATAgCATTCTTTCTTgAggAgggCAgCAAACgggAAgAg 5'
Thiol (SEQ ID NO: 1) B1 I2 DBCO
ATATAgCATTCTTTCTTgAggAgggCAgCAAACgggAAgAg 5' DBCO (SEQ ID NO: 1) B1
Amplifier H1 CgTAAAggAAgACTCTTCCCgTTTgCTgCCCTCCTCgCATTCTTTCTT 5'
Alexa Fluor 546 gAggAgggCAgCAAACgggAAgAg (SEQ ID NO: 2) 546 B1
Amplifier H2 gAggAgggCAgCAAACgggAAgAgTCTTCCTTTACgCTCTTCCCgTTTgCT 3'
Alexa Fluor 546 gCCCTCCTCAAgAAAgAATgC (SEQ ID NO: 3) 546 B1
Amplifier H1 CgTAAAggAAgACTCTTCCCgTTTgCTgCCCTCCTCgCATTCTTTCTT 5'
Biotin Terminal Biotin gAggAgggCAgCAAACgggAAgAg (SEQ ID NO: 2) B1
Amplifier H2 gAggAgggCAgCAAACgggAAgAgTCTTCCTTTACgCTCTTCCCgTTTgCT 3'
Biotin Terminal Biotin gCCCTCCTCAAgAAAgAATgC (SEQ ID NO: 3) B1
Amplifier H1 CgTAAAggAAgACTCTTCCCgTTTgCTgCCCTCCTCgCATTCTTTCTT
Internal Biotin Internal Biotin gAggAgggCAgCAAACgggAAgAg (SEQ ID
NO: 2) B1 Amplifier H2
gAggAgggCAgCAAACgggAAgAgTCTTCCTTTACgCTCTTCCCgTTTgCT Internal Biotin
Internal Biotin gCCCTCCTCAAgAAAgAATgC (SEQ ID NO: 3) B1 Amplifier
H1 CgTAAAggAAgACTCTTCCCgTTTgCTgCCCTCCTCgCATTCTTTCTT Internal Biotin
Internal Biotin gAggAgggCAgCAAACgggAAgAg (SEQ ID NO: 2) 5' Alexa
Fluor and 5'-488 448 B1 Amplifier H2
gAggAgggCAgCAAACgggAAgAgTCTTCCTTTACgCTCTTCCCgTTTgCT Internal Biotin
Internal Biotin gCCCTCCTCAAgAAAgAATgC (SEQ ID NO: 3) 3' Alexa Fluor
and 3'-488 488 B5 I2 ATATACACTTCATATCACTCACTCCCAATCTCTATCTACCC 5'
Biotin (SEQ ID NO: 4) B5 I2 Thiol
ATATACACTTCATATCACTCACTCCCAATCTCTATCTACCC 5' Thiol (SEQ ID NO: 4)
B5 I2 DBCO ATATACACTTCATATCACTCACTCCCAATCTCTATCTACCC 5' DBCO (SEQ
ID NO: 4) B5 Amplifier H1
ATTggATTTgTAgggTAgATAgAgATTgggAgTgAgCACTTCATATCACTC 5' Alexa Fluor
488 ACTCCCAATCTCTATCTACCC (SEQ ID NO: 5) 488 B5 Amplifier H2
CTCACTCCCAATCTCTATCTACCCTACAAATCCAATgggTAgATAgAg 3' Alexa Fluor 488
ATTgggAgTgAgTgATATgAAgTg (SEQ ID NO: 6) 488 B4 I2 Thiol
ATATACACATTTACAGACCTCAACCTACCTCCAACTCTCAC 5' Thiol (SEQ ID NO: 4)
B4 Amplifier H1 gAAgCgAATATggTgAgAgTTggAggTAggTTgAggCACATTTACAgAC
5' Alexa Fluor 647 CTCAACCTACCTCCAACTCTCAC (SEQ ID NO: 7) 647 B4
Amplifier H2 CCTCAACCTACCTCCAACTCTCACCATATTCgCTTCgTgAgAgTTg 3'
Alexa Fluor 647 gAggTAggTTgAggTCTgTAAATgTg (SEQ ID NO: 8) 647
TABLE-US-00002 TABLE 2 Antibodies Primary antibodies: Epitope
Vendor Cat. No. Dilution Incubation Time Tyrosine Hydroxylase
Millipore ab152 1:1000 Overnight at 4.degree. C. for brain (TH)
sections Choline acetyltransferase Millipore AB144P 1:500 Overnight
at 4.degree. C. for brain (ChAT) sections DOPA decarboxylase (AADC)
Abcam ab3905 1:500 24 h at 4.degree. C. for brain sections Neuronal
nitric oxide Sigma N7280 1:500 Overnight at 4.degree. C. for brain
synthase (nNOS) sections Dopamine Transporter (DAT) Millipore
MAB369 1:500 Overnight at 4.degree. C. for brain sections hGBP1
Santa Cruz sc-53857 1:1000 1 h at RT for Western blot GFP Thermo
Fisher A10259 1:1000 Overnight at 4.degree. C. for brain Scientific
sections; 1 h at RT for cultured cells and western blotting Ki67
eBioscience 14-5698-80 1:1000 1 h at RT for cultured cells Tom20
Santa Cruz sc-11415 1:1000 1 h at RT for cultured cells HA
BioLegend 901505 1:500 1 h at RT for Western blot Secondary
antibodies: Secondary ab. Vendor Label Cat. No. Dilution Incubation
Time Goat anti-rabbit Abcam Biotin ab6720 1:1000 2 h at RT for
brain sections Donkey anti-goat Jackson ImmunoResearch Biotin
705-065-147 1:1000 2 h at RT for brain sections Donkey anti-mouse
Jackson ImmunoResearch Biotin 715-065-151 1:1000 1 h at RT for
cultured cells Goat anti-rabbit Thermo Fisher scientific DNA HCR
31212 5 .mu.g mL.sup.-1 2 h at RT for brain initiators sections; 1
h at RT for Western blot and cultured cells Goat anti-rat Thermo
Fisher scientific DNA HCR 31220 5 .mu.g mL.sup.-1 2 h at RT for
brain initiators sections; 1 h at RT for Western blot and cultured
cells Fluorescent reagents: Name Vendor Label Cat. No. Conc.
Incubation Time SNAP-Surface Alexa NEB Alexa Fluor 546 S9132S 500
.mu.M, 30 min at RT Fluor 546 1:500-1:1000
TABLE-US-00003 TABLE 3 The protein sequence of smFP_GCN4. A total
of nine GCN4 tags are inserted into a superfolder GFP scaffold.
MEELLSKNYHLENEVARLKKGSGSGEELLSKNYHLENEVARLKKGSGSGE
ELLSKNYHLENEVARLKKGSGSGSKGEELFTGVVPILVELDGDVNGHKFS
VRGEGEGDATNGKLTLKFICTTGKLPVPWPTLVTTLGGGVQCFSRYPDHM
KRHDFFKSAMPEGYVQERTISFKDDGTYKTRAEVKFEGDTLVNRIELKGI
DFKEDGNILGHKLEYNFNSHNVYITADKQKNGIKANFKIRHNVEGSGSGE
ELLSKNYHLENEVARLKKGSGSGEELLSKNYHLENEVARLKKGSGSGEEL
LSKNYHLENEVARLKKGSGSGDGSVQLADHYQQNTPIGDGPVLLPDNHYL
STQSVLSKDPNEKRDHMVLLEFVTAAGITHGMDELYKGSGSGEELLSKNY
HLENEVARLKKGSGSGEELLSKNYHLENEVARLKKGSGSGEELLSKNYHL ENEVARLKK (SEQ
ID NO: 9)
Example 1
[0051] Multiplexed Labeling Using isHCR.
[0052] FIG. 1. (a) shows images of the dorsal striatum in mouse
brain sections double immunostained for TH (green) and choline
acetyltransferase (ChAT, red). The signals of each antigen were
visualized sequentially using corresponding biotinylated secondary
antibodies and isHCR. (b) HCR initiators were conjugated to
GFP-nanobodies (LaG-16-2) using SMCC as the linker. mGFP proteins
were expressed in the orbitofrontal cortex neurons in CaMKII-Cre
transgenic mice using adeno-associated virus (AAV) vectors. The GFP
signals in the superior colliculus were amplified using HCR
initiator-conjugated GFP-nanobody and isHCR-546. (c) Schematic of
rapid labeling using genetically encoded protein tags.
Functionalized HCR initiators bind directly to protein tags and
initiate the amplification process. AAV vectors that bear the
Cre-dependent double-floxed inverse (DIO) open reading frame
cassette containing genes encoding the SNAPf tag were constructed
and packaged into AAV particles. The AAV vectors were injected into
Cre-transgenic mice to achieve cell-type specific expression. (d)
Confocal images of HEK293T cells and mouse brain labeled by
SNAP-tag. The upper panel shows cells transiently expressing the
mSNAPf-tag. The middle panel shows the DRN from SERT-Cre mice
injected with AAV-DIO-mSNAPf. The bottom panel shows the medial
septum from SERT-Cre mice injected with AAV-DIO-4.times.SNAPf. The
tag-positive cells were labeled with benzylguanine-conjugated Alexa
Fluor 546 (BG-546) or isHCR-546. Scale bars, 50 .mu.m (a), 200
.mu.m (b), 100 .mu.m (d).
Example 2
[0053] Simultaneous Detection of Multiple Targets Using isHCR.
[0054] FIG. 2. (a) shows that two orthogonal HCR initiators can be
conjugated directly onto secondary antibodies using either SMCC or
Click Chemistry groups as linkers. (b) Western blot of a protein
mixture containing purified hGBP1 and purified GFP-hGBP1 proteins.
An anti-GFP primary antibody and an anti-hGBP1 primary antibody
were applied. The two primary antibodies were detected using two
secondary antibodies that were conjugated with different HCR
initiators. (c) Images of HEK 293T cells immunostained against the
nuclear protein Ki67 (red) and a mitochondria protein Tom20 (green)
using two HCR initiator-conjugated secondary antibodies. The
signals were then simultaneously amplified using isHCR-546 for Ki67
and isHCR-488 for Tom20. (d) Images of the dorsal striatum in mouse
brain sections double immunostained against dopamine transporter
(DAT, red) and neuronal nitric oxide synthase (nNOS, green) using
two HCR initiator-conjugated secondary antibodies. The signals were
then amplified simultaneously using isHCR-546 for DAT and isHCR-488
for nNOS. (e) Images of HEK 293T cells expressing three orthogonal
protein tags targeting different cellular locations. The signals
were simultaneously amplified using isHCR-488 for msmFP_GCN4,
isHCR-546 for mitoSNAP, and isHCR-647 for H2B-SpyTag. Scale bar, 10
.mu.m (c, e), 50 .mu.m (d).
Sequence CWU 1
1
9141DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 1atatagcatt ctttcttgag gagggcagca
aacgggaaga g 41272DNAArtificial SequenceDescription of Artificial
Sequence Synthetic polynucleotide 2cgtaaaggaa gactcttccc gtttgctgcc
ctcctcgcat tctttcttga ggagggcagc 60aaacgggaag ag 72372DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
3gaggagggca gcaaacggga agagtcttcc tttacgctct tcccgtttgc tgccctcctc
60aagaaagaat gc 72441DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 4atatacactt catatcactc
actcccaatc tctatctacc c 41572DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 5attggatttg tagggtagat
agagattggg agtgagcact tcatatcact cactcccaat 60ctctatctac cc
72672DNAArtificial SequenceDescription of Artificial Sequence
Synthetic polynucleotide 6ctcactccca atctctatct accctacaaa
tccaatgggt agatagagat tgggagtgag 60tgatatgaag tg 72772DNAArtificial
SequenceDescription of Artificial Sequence Synthetic polynucleotide
7gaagcgaata tggtgagagt tggaggtagg ttgaggcaca tttacagacc tcaacctacc
60tccaactctc ac 72872DNAArtificial SequenceDescription of
Artificial Sequence Synthetic polynucleotide 8cctcaaccta cctccaactc
tcaccatatt cgcttcgtga gagttggagg taggttgagg 60tctgtaaatg tg
729459PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 9Met Glu Glu Leu Leu Ser Lys Asn Tyr His Leu
Glu Asn Glu Val Ala1 5 10 15Arg Leu Lys Lys Gly Ser Gly Ser Gly Glu
Glu Leu Leu Ser Lys Asn 20 25 30Tyr His Leu Glu Asn Glu Val Ala Arg
Leu Lys Lys Gly Ser Gly Ser 35 40 45Gly Glu Glu Leu Leu Ser Lys Asn
Tyr His Leu Glu Asn Glu Val Ala 50 55 60Arg Leu Lys Lys Gly Ser Gly
Ser Gly Ser Lys Gly Glu Glu Leu Phe65 70 75 80Thr Gly Val Val Pro
Ile Leu Val Glu Leu Asp Gly Asp Val Asn Gly 85 90 95His Lys Phe Ser
Val Arg Gly Glu Gly Glu Gly Asp Ala Thr Asn Gly 100 105 110Lys Leu
Thr Leu Lys Phe Ile Cys Thr Thr Gly Lys Leu Pro Val Pro 115 120
125Trp Pro Thr Leu Val Thr Thr Leu Gly Gly Gly Val Gln Cys Phe Ser
130 135 140Arg Tyr Pro Asp His Met Lys Arg His Asp Phe Phe Lys Ser
Ala Met145 150 155 160Pro Glu Gly Tyr Val Gln Glu Arg Thr Ile Ser
Phe Lys Asp Asp Gly 165 170 175Thr Tyr Lys Thr Arg Ala Glu Val Lys
Phe Glu Gly Asp Thr Leu Val 180 185 190Asn Arg Ile Glu Leu Lys Gly
Ile Asp Phe Lys Glu Asp Gly Asn Ile 195 200 205Leu Gly His Lys Leu
Glu Tyr Asn Phe Asn Ser His Asn Val Tyr Ile 210 215 220Thr Ala Asp
Lys Gln Lys Asn Gly Ile Lys Ala Asn Phe Lys Ile Arg225 230 235
240His Asn Val Glu Gly Ser Gly Ser Gly Glu Glu Leu Leu Ser Lys Asn
245 250 255Tyr His Leu Glu Asn Glu Val Ala Arg Leu Lys Lys Gly Ser
Gly Ser 260 265 270Gly Glu Glu Leu Leu Ser Lys Asn Tyr His Leu Glu
Asn Glu Val Ala 275 280 285Arg Leu Lys Lys Gly Ser Gly Ser Gly Glu
Glu Leu Leu Ser Lys Asn 290 295 300Tyr His Leu Glu Asn Glu Val Ala
Arg Leu Lys Lys Gly Ser Gly Ser305 310 315 320Gly Asp Gly Ser Val
Gln Leu Ala Asp His Tyr Gln Gln Asn Thr Pro 325 330 335Ile Gly Asp
Gly Pro Val Leu Leu Pro Asp Asn His Tyr Leu Ser Thr 340 345 350Gln
Ser Val Leu Ser Lys Asp Pro Asn Glu Lys Arg Asp His Met Val 355 360
365Leu Leu Glu Phe Val Thr Ala Ala Gly Ile Thr His Gly Met Asp Glu
370 375 380Leu Tyr Lys Gly Ser Gly Ser Gly Glu Glu Leu Leu Ser Lys
Asn Tyr385 390 395 400His Leu Glu Asn Glu Val Ala Arg Leu Lys Lys
Gly Ser Gly Ser Gly 405 410 415Glu Glu Leu Leu Ser Lys Asn Tyr His
Leu Glu Asn Glu Val Ala Arg 420 425 430Leu Lys Lys Gly Ser Gly Ser
Gly Glu Glu Leu Leu Ser Lys Asn Tyr 435 440 445His Leu Glu Asn Glu
Val Ala Arg Leu Lys Lys 450 455
* * * * *